Method for reducing data rate during transmission of object-related data between two computer elements communicating within time limits

ABSTRACT

A process for reducing required data throughput when transmitting object or process oriented data between user areas communicating within time conditions, uses a data transmission device having at least one communication module to which at least one external unit is assigned. A sending communication module extrapolates the data to be sent and sends the data to a receiving communication module when a comparison value formed of the respective current data and the extrapolated data at least reaches a desired quantity. The receiving communication module extrapolates received data and provides it for use by an external unit until current data are received.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a method and apparatus for reducing datathroughput when transmitting data which characterize processes orobjects, between computing elements communicating under time control,particularly in real time.

In computer units which communicate with one another in real time, themaximum bandwidths or transmission rates of the data transmissiondevices, including the protocol used for such communication, represent abottleneck in the data interchange between the computer units. Usually,data quantities which exceed the maximum bandwidth are deleted ordelayed during the transmission; and the sending computer has noinformation concerning the cutting-off or the delay of data quantities,including the portion of the data which has not been transmitted. As theresult, the sending computer unit itself has no control over which datathe receiving computer unit has received. It is therefore a disadvantagein the state of the art that it is essentially only possible either totolerate this uncertainty or to accept additional managementexpenditures with respect to data transmission reliability in order tocontrol the data transmitted to the receiving computer unit. Accordingto the state of the art, these advantages are overcome by usingrelatively high-expenditure (and therefore high-cost) data transmissiondevices with a large transmission bandwidth.

It is therefore an object of the invention to provide a process andapparatus for transmitting data between computer units communicatingunder time control, which minimizes the data quantities to be exchangedbetween the computer units, while simultaneously preserving theinformation concerning the respective connected computer units, which ispresent in the interchanging computer units.

This and other objects and advantages are achieved by the communicationmethod and apparatus according to the invention, in which, during eachtransmission interval, a sending communication computer decides whetherto send updated (current) data to another communication computer in adifferent user area, using at least one extrapolation process which isrunning on both data-interchanging communication computers. In thesending communication computer, the current data, generated by externalunits assigned to the sending communication computer are compared withcorresponding data extrapolated by the sending computer. Since the sameextrapolated data are also generated in the same manner in the receivingcommunication computer for use in the external units assigned to it, thesending communication computer, taking into account the transmissionpath, has information concerning the data which are present in thereceiving user area. On this basis, and as a result of the comparison ofextrapolated data with current data, the sending communication computerdecides whether to send current data to the receiving user area.

In order to design the extrapolation processes efficiently, thecharacteristics of objects or processes which are described by the datato be transmitted, are structured in corresponding formats such that, onthe one hand, the objects or processes are described by as few dataexpenditures as possible and, on the other hand, the extrapolationprocesses achieve maximum efficiency in use of computing time. As aresult, the data quantities to be transmitted per time unit aresignificantly reduced. Furthermore, the quality of the objects processedby the system or the number of described objects can be increased, whiletransmitting the same data quantities as in the state of the art.

The comparison (difference) values as between the current andextrapolated data sets are compared with threshold values for thedecision concerning transmission. Together with a continuously updatedlist of priorities (by means of which a sequence, and thus atransmission point in time of the data to be transmitted is defined),these threshold values determine a maximal transmission error.

The system for transmission of data according to the inventionparticularly also has the advantage that, for communication betweencomputer systems producing large quantities of data, it is possible touse data transmission devices with relatively low transmissionbandwidths, which are reasonable in cost.

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of the computer system according to the invention withtwo user areas and a data transmission line;

FIG. 2 is a view of a simulation system also with two user areas as anapplication example of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a computer system with a first user area 1 and asecond user area 2, which are connected with one another by way of adata transmission device 3, which may also comprise storage media. Inthe first user area 1, a communication module or a communicationcomputer 10 is connected to the data transmission device 3. Thecommunication computer 10 is connected by way of corresponding signal ordata transmission lines with external units 11, 12, 13, which may becomputer units or a tape recorder. Likewise, a communication module orcommunication computer 20 connected to the data transmission device 3 isprovided in the second user area 2. This communication computer 20 isalso connected by way of corresponding signal or data transmission lineswith external units 21, 22, 23 of the second user area 2. The externalunits 11, 12, 13 and 21, 22, 23 continuously provide data, which may begenerated independently of the communications computers 10, 20, andwhich they transmit to the other communication computers 10, 20. Thecommunication computers 10, 20 communicate with one another under timeconditions; that is, they mutually exchange data which they receivedfrom the respective assigned external units 11, 12, 13 and 21, 22, 23.The communication computers 10, 20 are connected with a timer 30, andmay have functions which control at least parts of the communicationbetween external units.

If, for example, the communication computer 10 receives data from theexternal units 11, 12, 13 connected with it, which are to be transmittedto the communication computer 20 by way of the data transmission device3, these data are transmitted by way of the data transmission device 3,using a defined data transmission protocol, in the form of data sets ordata set packets of a defined transmission format. The data transmissiondevice 3 has a limited bandwidth, which may be determined, for example,by the maximum data throughput of the transmission channel, such as adata line or a radio connection, by the memory size of an assignedstorage unit, or by the data processing speed of the data processingdevices provided for data transmission (for example, of a crypter). Thegenerated and interchanged data preferably are object-oriented data;that is, data which describe objects or characteristics of objects.

According to the invention, in the case of the transmission formats, adistinction is made between data which can be changed by way of thetransmission steps, and data which cannot (quasi-static data). These maybe numerical values as well as logic values. The quasi-static datacomprise, for example, data which describe the characteristics ofobjects which remain the same over time, while the data which can bechanged by way of the transmission steps describe, for example, thetime-variable behavior of these objects. The quasi-static data need betransmitted only at the beginning of the whole transmission process andat the relatively rare points in time at which they change. A device orfunction is therefore provided in the respective sending communicationcomputers 10, 20, which determines when a type of quasi-static data haschanged, and provides the transmission of corresponding quasi-staticdata. Furthermore, the respective sending communication computer 10, 20can initiate and cause the transmission of quasi-static data if thiscommunication computer 10, 20 has determined that a sufficient amount oftransmission bandwidth is still available for the correspondingtransmission step in the data transmission device 3.

The changeable data are described in application-specific orobject-specific formats for the data sets. For the data to betransmitted, extrapolation processes exist in the interchangingcommunication computers 10, 20, which may represent an estimate of thefunctions implemented in the assigned external units, or anextrapolation of new values with respect to time on the basis of oldvalues. Analogous to the functions provided in the external units, theseextrapolation processes may be mathematical or logic functions, such asdata bank functions. By means of the extrapolation processes, datacorresponding to those which are present in a communication computer 10,20 at the time of a transmission step may be determined for a laterpoint in time. The extrapolation processes provided in a communicationcomputer 10, 20 may depend on the number and type of the functions whichare implemented in the assigned external units 11, 12, 13 and 21, 22,23. However, they may also be designed independently of the functions ofthe external units 11, 12, 13 and 21, 22, 23 according to generalprinciples. In each case, the extrapolation processes implemented in acommunication computer of a user area perform the function (in parallelto the generation of current data) of calculating values for theexternal units in the receiving user area, on the basis of specificfunctions in the external units of the sending user area. Theextrapolations in the receiving user area thus determine values or datafor points in time for which the respective current data are determined,on the basis of specific functions in the external units of the sendinguser area.

In determining the time value on which the extrapolation is based, thetransmission time of the data from the sending communication computer 10to the receiving communication computer 20 is taken into account. In thecase of the sending communication computer, for example, a transmissiontime is used which is determined in advance. In the case of thereceiving communication computer 20, the transmission time for aparticular data set is determined by a time stamp provided by thesending communication computer 10 based on a signal of the timer 30corresponding to the sending point in time, and the absolute timedefined by the timer 30 for the receiving point in time. This actualtransmission time is preferably transmitted in turn to the communicationcomputer which has sent the data, and is used later to estimate thetransmission time by the sending communication computer. Theextrapolation processes are optimized or adapted to the data or to thecorresponding data set formats of the application or their objects andvice-versa, with respect to the computing time. For the respectiveoperating time of the computer system according to the invention, theextrapolation processes are constantly active in the correspondingcommunication computers 10, 20. In the sending communication computer,the same extrapolation process is active which runs in the receivingcommunication computer, and is used for generating the same data, andtherefore information on the basis of which the operation takes place inthe respective receiving user area. The current data sent to thereceiving communication computer or the data extrapolated there arepreferably used as input data for the functions which are implemented inthe external units of the respective receiving user area.

For example, the communication computer 10 in each case sends currentdata of the corresponding specific data set format (that is, a group ofdata types by means of which the objects to be described by the data canbe efficiently described) to the receiving communication computer 20.These current data are generated by the external units which areassigned to the sending communication computer and which performspecific application programs or functions, preferably for (among otherthings) time-variable description of objects. Such current data aregenerally required at least partially by the functions which run onexternal units in the respective receiving user area. Then,independently of one another the sending communication computer 10 andthe receiving communication computer 20 use the same specificextrapolation processes which are applied to data with the same timebasis defined by the timer 30, to determine data for a later point intime (for example, for a later transmission step). The data extrapolatedby the receiving communication computer 20 and the data it receives fromtime to time are used as input quantities for the object-orientedfunctions which run in the external units of the receiving user area.Independently thereof, the sending communication computer 10 receivesfrom the external units 11, 12, 13 assigned to it (on which the functionor object-oriented application programs run) additional current datawhich, for a particular subsequent point in time, correspond to therespective data which were or are obtained by the correspondingextrapolation.

The current data are compared in the communication computer 10 with theextrapolated data. In parallel thereto, the application programs orfunctions, which run in the receiving user area, operate on the basis ofthe data last generated by the sending user area or communicationcomputer 10 and transmitted to the receiving communication computer 20or on the basis of the data obtained by the receiving communicationcomputer 20 by extrapolation. If, during the comparison in the sendingcommunication computer 10, the resulting comparison values exceed athreshold value (at which the transmission time determined by thesending communication computer 10 and which is determined for eachobject described by the respective data set or an object related theretospecifically before or during the operation of the computer system), atransmission of the data set formed of these data is initiated. (Thatis, its transmission is noted down.) On the basis of the transmissiontime concretely determined by means of the timer 30, the receivingcommunication computer 20 relates the respective received current datato the point in time at which they were generated in the sending userarea or its external units or to which they relate. By taking intoaccount the transmission path, the sending communication computer 10 cancompare the current data with the data used in the application programsof the external units 21, 22, 23 in the receiving user area 2, and onthe basis of such comparison, can also obtain information concerning theprecision with which the functions of the external units 21, 22, 12 arerunning.

For the decision as to which data are actually sent by the sendingcommunication computer 10 to the receiving communication computer 20, alist of priorities is provided which is constantly updated by thesending communication computer 10. This list of priorities represents anevaluation of a variable number of entries which refer to the data setsto be sent. In this case, the data and the contents themselves arepreferably not entered into the list of priorities, the entriesincluding only references to the respective data sets. By means of thelist of priorities (which is to be updated constantly), it is determinedthat the data to which the entries refer in each case are sent to thereceiving communication computer 20, which is performed in the order orsequence in which the entries are listed in the list of priorities.

The order or sequence, and thus the significance, of the entries and ofthe pertaining data sets in the list of priorities required with respectto the operational reliability, is determined by given criteria. Forthis determination, for example, the following are relevant: for whichtime period the data of a certain type were no longer updated by thecommunication computer 20 or were sent irrespective of an updating;which meaning and significance attributed with respect to thefunctionality of the whole computer system is assigned to the data setspertaining to the entries; and the size of the data sets. In the orderor sequence of the entries of the priority list, the data sets to whichthe respective entries refer are sent by the sending communicationcomputer 10 to the receiving communication computer 20.

From the sum of the entries listed in the list of priorities, thesending communication computer 10 determines the transmission bandwidthwhich is required to ensure the operational reliability of the entirecomputer system. If the required transmission bandwidth exceeds thebandwidth defined by the data transmission device 30, the sendingcommunication computer 10 can take appropriate countermeasures. Thesemay include the following: Increase of the physical bandwidth of thedata transmission device 30, for example, by connecting anothertransmission line, or a temporary reduction of the bandwidth requiredfor the functionality of the entire computer system by a temporarychange of the criteria for the determination of the list of priorities,for example, by a raising of the tolerance limit defined by thethreshold values.

The function of the data transmission was described above for a case inwhich the communication computer 10 is the sending unit and thecommunication computer 20 is the receiving unit. This operation cansimultaneously also take place in the reverse direction. In addition,the described sequences can also be used when data are to be sent forthe description of different objects in one or the other direction.

The computer system according to the invention may also have more thantwo user areas. In this case, one or several user area(s) may compriseone or several communication computer(s). In addition, only onecommunication computer may be provided for several user areas. Also, oneor several additional communication computer(s) may be connected to afirst communication computer, which additional communication computer(s)may also be subordinate to the first communication computer.

The timer 30 has the function of indicating to the communicationcomputers connected to it an absolute time; that is, a time which isindependent of the sequence in the communicating computers. Thisfunction can be carried out by means of other devices available in thestate of the art, for example, by standard time clocks.

By separating data into static and dynamic data, the data set to be sentfrequently contains only the highly time-variable or dynamic data, sothat the data set size is smaller than the data set sent in the state ofthe art with each transmission step and provided with the same contents.As a result, the data quantity to be transmitted is reduced.

In an alternative embodiment, several objects may also be described bymeans of one data set.

As an alternative to the described embodiments, the extrapolationprocesses in the communication modules 10, 20 or computers may differ.However, they must be suitable for building up and having availablewithin the respective communication module 10, 20 a knowledge of theinformation present in the respective assigned communication module 10,20.

The transmission times for the transmission of the data from the sendingto the receiving communication computer or module 10, 20 estimated ordetermined during the extrapolation in the preferred embodiment may alsobe omitted if permitted by the required overall precision of the systemaccording to the invention.

In the receiving communication module, an estimated transmission timecan also be used when defining the extrapolation time.

Another advantage of the invention is that it generates data sets whichare specific to the simulated objects. These data sets contain data bymeans of which a particularly efficient extrapolation can be carried outwith a minimal number of data, so that a further reduction of thetransmission bandwidth requirements is achieved.

By establishing a constantly updated list of priorities and controllingthe utilization of the transmission system, its bandwidth can beoptimally utilized by selection of the data sets to be transmitted. Thepriority list can be updated at predetermined time intervals orautomatically according to known processes.

In the following, the invention will be described by means of thesimulation system illustrated in FIG. 2.

FIG. 2 illustrates a simulation system 100 in which several locallymutually separated flight simulators operate in a predetermined airspace, for example, in groups, with or against one another. FIG. 2 showsa first simulation center 101 and a second simulation center 102. Thetwo simulation centers 101, 102 each have a communication module or acommunication computer 111, 112, to which several simulation devices133, 134 are connected by means of the corresponding interfaces (I/F).In the first simulation center 101, a first flight simulator 121 and asecond flight simulator 122 (each of which may be for example, anairplane simulation, a weapons system simulation, a cockpit simulation,an outside-view simulation or others are connected to the simulationdevices 133 assigned to these interfaces. Two airplane simulators 123,124 are also connected as simulation devices to the communicationcomputer 112 of the second simulation center 102. One shared memory 131,132 provided in each of the two simulation centers 101, 102 is connectedwith the communication computer 111, 112 and with the pertaining flightsimulators 121, 122 and 123, 124, 125. Data interchange among thesimulation devices 133 and 134 as well as between the simulation devices113 and the assigned communication computer 111 is carried out by way ofthe shared memory 131, 132. Between the first simulation center 101 andthe second simulation center 102, a data transmission device or atransmission system 130 transmits data from one communication computerto another via a transmission medium.

The communication computers 111, 112 are connected with a timer 140.

In the following, the method of operation of the simulation systemaccording to FIG. 2 is described:

The two simulation centers 101 and 102 operate in real time and may besituated at locations far remote from one another. As a result, forexample, by means of the simulation system 100, tactical air combatmaneuvers of two hostile groups of flight simulators can be carried outin a predetermined scenario, with the respective flight-related ortactical decisions made in each simulation center 101, 102 independentlyof one another.

The flight simulators 121, 122 and 123, 124, 125 normally continuously(or at a defined updating or iteration rate) supply to the shared memory131, 132 data (changing by way of iteration steps) concerning theircondition and the values calculated by their functions. Thus, the flightsimulation supplies, for example, information concerning the momentaryposition, velocity, acceleration, angular velocities, angularaccelerations of the airplane model as well as concerning its attitudeand direction. At the updating rate, the flight simulators 121, 122,123, 124 also supply data to their assigned communication computers 111,112 concerning the condition of the respective plane which is flown bymeans of the corresponding cockpit device in a simulation.

Furthermore, the flight simulators 121, 122 and 123, 124, 125 supplyquasi-static data concerning the airplane type, possibly its subtypes,status, affiliation with a formation as well as flight-technical andtactical parameters.

The weapons system simulation sends quasi-static data of guidedmissiles, for example, with respect to the type, possible subtypes,status, such as the flight condition or achieved hits, affiliation witha formation or with a selected target. As dynamic data, on the one hand,guided-missile-specific data are sent to the shared memory 131, 132,specifically preferably the position and speed of the missile. On theother hand, the weapons system simulation sends emission data, forexample, radar data or interference data (jammers) and simulation datafor defense measures to the respective shared memories 131, 132.

The communication computers have access to the data of the flightsimulators 121, 122 and 123, 124, 125 via the shared memories 131, 132.Those data which are relevant, for example, to the cockpit simulationsof the flight simulators 123, 124, 125 of the second simulation center102 with respect to the first simulation center 101 are sent by thefirst communication computer 111 to the second communication computer112. For a further illustration of the method of operation, in thefollowing, the communication computer 111 will be considered to be thesending communication computer.

The receiving communication computer 112 receives the quasi-static anddynamic data sent by the communication computer 111 and usesapplication-specific extrapolation algorithms to extrapolate thesedynamic data to defined later points in time, until it receives a newdata set from the communication computer 111. During this extrapolation,the time duration of a possible transmission of the data to simulationdevices 134 of another simulation center 102 is taken into account. Thecommunication computer 112 provides the quasi-static data by way of theshared memory 132 to the flight simulators 123, 124, 125.

Both communication computers 111, 112, which are part of the assignedsimulation centers 101, 102, implement the same specific extrapolationalgorithms and use them to extrapolate in parallel data for later pointsin time, based on the sent and received data, taking into account thetransmission time for the respective transmission between the simulationcomputers. The sending communication computer 111 compares the dataobtained by extrapolation with the current data generated by theassigned flight simulators 121, 122 and data present in the sharedmemory 131. If this comparison results in differential values which arelarger than predetermined threshold values, the communication computer111 initiates the transmission of the current data of the flightsimulators 121, 122 by way of the data transmission system 130 to thecommunication computer 112. These current transmitted data form the newstarting point for a new extrapolation.

The actual transmission takes place on the basis of the list ofpriorities described in connection with FIG. 1. These are continuouslyupdated in the operation by the communication computer 111, in whichentries with references to corresponding data sets on the basis ofconcrete criteria, which may also change in the course of the process,are arranged in a priority sequence corresponding to the transmissionsequence.

In the present application, the positions of the corresponding entriesof the flight simulators 121, 122 in the list of priorities are definedaccording to: i) the amount by which the differential values between thecurrent and the extrapolated data have exceeded a predeterminedthreshold value; ii) the importance of the current data; and/or iii) apossibly defined minimal updating rate. The importance of data isdetermined, for example, on the basis of the required computingprecision of the functions of the flight simulators 121, 122. Forexample, airplanes within the range of a gun are assigned a higherprecision and thus a higher importance than those objects which cannotyet be detected by radar. Airplane data which are generated by theairplane simulation may also have a greater importance than missile databecause a higher precision is normally required for the description ofthe flight path of an airplane.

In order to control and direct the quantity of the data sent by thecommunication computer 111 by way of the transmission system 130, thethreshold values for the comparison between the extrapolated and theupdated data can be modified by the respective communication computer111. For this purpose, for example, for missiles, a lower and an upperlimit of threshold values with respect to the position vector and thespeed vector are used as initialization parameters.

The data sent to the communication computer 112 are transmitted in theform of defined data sets, which depends on the function of the flightsimulators 121, 122 which these data sets generate (for example, theflight simulation or the weapons system simulation). For example, thefollowing data sets are provided in the described application: a dataset with the above-mentioned quasi-static data in each case for asimulated airplane and in each case for a missile which is generated andsent at least once in the course of the life cycle of the correspondingobject; a data set with the dynamic data for one airplane simulationrespectively which is to be sent as a function of the predeterminedthreshold values and which preferably comprises the position, the speed,the acceleration, the orientation (in quaternions), the angular velocityand the angular acceleration; a data set with the dynamic data for onemissile respectively controlled by the weapons system simulation, whichpreferably contains its position and speed; a data set with data, forexample, for objects, such as radar emissions, jammer simulations ofdefense measures, these data being transmitted in the form of thecorresponding data set either always as soon as they were generated orbeing sent in a fixed time pattern.

When the data sets of the quasi-static dynamic or other data are sent,these data sets are provided with an identification of the generatingflight simulator 121, 122. In addition, the data sets of the dynamicdata receive a time stamp.

By the use of quaternions to describe the orientation of simulatedobjects, a particularly efficient extrapolation of these data can becarried out. This permits, on the one hand, a data reduction whilesimultaneously maintaining predetermined error tolerance limits. On theother hand, during the transmission of the same data quantity astransmitted without the process according to the invention (that is,according to the state of the art), a better quality of the values isachieved because of the values transmitted by the application programswithin the respective system.

It is important to note that the structures of the data sets aredesigned specifically for the description of the simulated objects andsimultaneously permit an efficient extrapolation (that is, anextrapolation by means of relatively few data). As a result, in theevent of a corresponding deviation of the extrapolated data from thecurrent data, only a few data need be transmitted to the receivingsimulation center.

An above-described data set packet is sent per transmission step to thesecond communication computer 112. The transmission of all interchangeddata need not take place in a timed manner in the case of the processaccording to the invention. A transmission step in this case is only asingle transmission step. In order to take into account the transmissiontime (which occurs only in a simulation system but not in reality), thedata to be sent are precomputed to the receiving point in time. In thiscase, the transmission time which is used was determined in thepreceding transmission steps by means of the timer 140 (based on thetime stamp added to the respective data set when sending it off and theabsolute times transmitted by the timer to the correspondingcommunication computers).

The above statements refer to the method of operation of the simulationsystem for the transmission from the communication computer 111 to thecommunication computer 112. Analogously, they also apply to the reversetransmission operation.

In an alternative embodiment of the air space simulation system 100,each simulation center 101, 102 may comprise more than two communicationcomputers 111, 112. The air space simulation system 100 according to theinvention may also comprise more than two simulation centers which eachhave at least one communication computer 111, 112.

The relationship of functions described by means of the firstcommunication computer 101 is preferably also implemented in the secondcommunication computer 112 as well as optionally in the additionalcommunication computers.

The system according to the invention can, for example, also be providedfor the alignment of simulations with the corresponding real systems,instruments or vehicles, in which case the same time base must always beused for the measurement data to be fed into the system to be aligned aswell as for the measurement data to be fed into the simulated system.

The foregoing disclosure has been set forth merely to illustrate theinvention and is not intended to be limiting. Since modifications of thedisclosed embodiments incorporating the spirit and substance of theinvention may occur to persons skilled in the art, the invention shouldbe construed to include everything within the scope of the appendedclaims and equivalents thereof.

What is claimed is:
 1. Process for reducing a required data throughputin transmission of at least partially time variable information whichcharacterizes an object or process, by means of a protocol betweencommunication modules which communicate with one another under timecontrol by way of a data transmission device, each communication modulebeing coupled to at least one external unit for providing and utilizingtransmitted data, and each communication module being connected with atimer, said process comprising: a sending communication module in asending user area performs a first time-related extrapolation of data tobe sent, using a predetermined algorithm and taking into account atransmission time, said data to be sent comprising current actual dataprovided by an external unit coupled to said sending communicationsmodule; said sending communication module compares said current actualdata currently provided by said external unit with temporallycorresponding extrapolated data, and determines a comparison value basedthereon; said sending communication module transmits said current actualdata to a receiving communication module in a receiving user area whensaid comparison value reaches or exceeds a desired quantity; saidreceiving communication module, performs a second time-relatedextrapolation of data received from the sending communication module,said second time related extrapolation corresponding to said firsttime-related extrapolation performed by the sending communicationmodule, and using the same predetermined algorithm; and said receivingcommunication module provides extrapolated data for use by an externalunit coupled thereto until the receiving communication module hasreceived further current actual data; wherein in extrapolation of thereceived data, the receiving communication module takes into account atime delay due to transmission time required for transmission of datafrom the sending to the receiving communication module; theextrapolation is specific for at least one time-variable object orprocess characterized by the data; the data are defined in the form ofdata sets which reflect characteristics of the object or process to becharacterized, which characteristics can be extrapolated; the desiredquantity used for the comparison between the current actual and theextrapolated data can be set during the process, based on a dataquantity to be sent for a particular point in time relative to anavailable data transmission bandwidth; for defining a sequence in whichdata are sent in the form of data sets, a continuously updated list ofpriorities is provided which comprises an arrangement of references todata sets; and the sequence is determined by a weighting thesignificance of respective data sets in terms of functionality of theexternal unit at least of the sending user area, and by a time durationwithin which a particular data set has no longer been sent untilupdating of the list of priorities.
 2. The process according to claim 1,wherein: the sending communication module formats data to be sent, intoa data set with data which are invariable for a relatively long time,and a data set with data which are variable in the course of a smallnumber of iteration steps; the data set with the invariable data aresent according to time intervals which are several times larger thantime intervals according to which the variable data are sent; and thedata set with the variable data are used for extrapolation.
 3. Theprocess according to claim 1, wherein the first and secondextrapolations are mathematical extrapolations.
 4. The process accordingto claim 1, wherein the comparison value is a differential value and thedesired quantity is a threshold value.
 5. The process according to claim1 wherein said receiving communications module performs saidtime-related extrapolation independently of the time-relatedextrapolation performed in said sending communications module.
 6. Anapparatus for transmitting at least partially time variable transmissiondata which characterize an object or process, comprising: a plurality ofcommunication modules, each of which is coupled to send and receivetransmission data to and from other communication modules via atransmission medium in a time controlled manner, and each of which isadapted to interchange transmitted and received transmission data withat least one external unit associated therewith, which external unitgenerates and provides to the associated communication moduletransmission data actual which characterize an object or process, anduses transmission data received from said associated communicationmodule; wherein each of said communication modules includes means forextrapolating actual data forward in time using a predeterminedalgorithm, taking into account a transmission time for transmission ofdata; comparing current actual data currently provided by an externalunit associated therewith in a sending user area, with extrapolated datacorresponding thereto and determining a comparison value based thereon;transmitting said current actual data to a receiving communicationmodule in a receiving user area when said comparison value reaches orexceeds a desired quantity; performing a time extrapolation oftransmission data received from a sending communication module whichsent such data, in parallel to the extrapolation performed by thesending communication module and using the same predetermined algorithm;and said receiving communication module providing extrapolated data foruse by an external unit coupled thereto until the receivingcommunication module has received further current actual data; whereinin extrapolation of the received data, the receiving communicationmodule takes into account a time delay due to transmission time requiredfor transmission of data from the sending to the receiving communicationmodule; the extrapolation is specific for at least one time-variableobject or process characterized by the data; the data are defined in theform of data sets which reflect characteristics of the object or processto be characterized, which characteristics can be extrapolated; thedesired quantity used for the comparison between the current actual dataand the extrapolated data can be set during the process, based on a dataquantity to be sent for a particular point in time relative to anavailable data transmission bandwidth; for defining a sequence in whichdata are sent in the form of data sets, a continuously updated list ofpriorities is provided which comprises an arrangement of references todata sets; and the sequence is determined by a weighting thesignificance of respective data sets in terms of functionality of theexternal unit at least of the sending user area, and by a time durationwithin which a particular data set has no longer been sent untilupdating of the list of priorities.
 7. The apparatus according to claims6, wherein: the sending communication module formats data to be sent,into a data set with data which are invariable for a relatively longtime, and a data set with data which are variable in the course of asmall number of iteration steps; the data set with the invariable dataare sent according to time intervals which are several times larger thantime intervals according to which the variable data are sent; and thedata set with the variable data are used for extrapolation.
 8. Theapparatus according to claim 6, wherein the first and secondextrapolations are mathematical extrapolations.
 9. The apparatusaccording to claim 6, wherein the comparison value is a differentialvalue and the desired quantity is a threshold value.
 10. The apparatusaccording to claim 6, wherein said external units comprise simulatordevices for simulating an object or process.
 11. The apparatus accordingto claim 6 wherein said receiving communications module performs saidtime-related extrapolation independently of the time-relatedextrapolation performed in said sending communications module. 12.Method for reducing a required data throughput in the transmission of atleast partially time-variable object-related data between respectivecommunications modules, by means of a protocol communicating within timeconditions through a data transmission device, each of which modules isassociated with at least one external unit for providing or using theobject-related data, and each of which modules is connected with atimer, wherein: a first time extrapolation of data which are to betransmitted is performed in a sending communication module according toa predetermined extrapolation method, taking into consideration atransmission time for transmission of data from the sendingcommunications module to a receiving communications module; data aretransmitted to a respective receiving communications module when acomparative value formed from current data and the extrapolated datareaches or exceeds a set value; a second time extrapolation oftransmitted data is performed in the receiving communications module,using said predetermined extrapolation method, in parallel to andindependent of the extrapolation performed in the sending communicationsmodule, and using an extrapolation time which takes into consideration atime delay due to said transmission time; an external unit assigned tothe receiving communications module uses extrapolated data until thereceiving communications module has received new data; the desiredquantity used for the comparison between the current actual and theextrapolated data can be set during the process, based on a dataquantity to be sent for a particular point in time relative to anavailable data transmission bandwidth; for defining a sequence in whichdata are sent in the form of data sets, a continuously updated list ofpriorities is provided which comprises an arrangement of references todata sets; and the sequence is determined by a weighting thesignificance of respective data sets in terms of functionality of theexternal unit at least of the sending user area, and by a time durationwithin which a particular data set has no longer been sent untilupdating of the list of priorities.